Chemiluminescent devices are non-incandescent products which produce light from a mixture of chemicals. These devices are most valuable for emergency lighting applications such as when normal electrical power service is interrupted. Power interruptions often accompany storms, floods, hurricanes, fires, earthquakes and the like natural disasters. Additionally, because chemiluminescent devices do not rely on electricity for operation, they are readily and reliably used in wet environments, even under water, where electrically powered devices could short out and fail.
Also unique to chemiluminescent devices are their ability to produce light without generating heat. Since chemiluminescent devices are not electrically operated or sources of ignition, they are ideally suited to emergency situations such as the aforementioned disasters. For instance, in situations where flammable vapors such as gasoline or natural gas may be present, conventional illumination such as candles, lanterns or even flashlights pose extreme danger as potential sources of ignition.
The production of light from a chemiluminescent device is conventionally based upon the reaction of a catalyzed hydrogen peroxide mixture (activator) with an oxalate. Chemiluminescent devices are also commercially available in a variety of visible colors as well as non-visible infrared which may be viewed through the use of special optical systems. A great variety of chemical reagents for producing light by chemiluminescent reaction are known. A typical commercially available chemiluminescent device that produces a yellow color can be created from the following constituents: Dibutyl Phthalate 66.45%; Dimethyl Phthalate 20-35%; CPPO bis(2,4,5-trichloro-6-carbopentoxyphenyl) oxalate 8.33%; T-butyl alcohol 3.3%; 90% aq. Hydrogen Peroxide 1.32%; CBPEA 1-chloro-9,10-bis(phenylethynyl) anthracene 0.23%; and Sodium Salicylate 0.0025%. One example of such a chemiluminescent device is taught in U.S. Pat. No. 5,043,851.
The activator reagent is typically contained within a breakable vial (s) which, when broken, admixes with the oxalate reagent to produce the chemiluminescent light. The activator and oxalate placement may be reversed. Since the object of this type of device is to produce usable light output, the containment vessel is made of a clear or translucent material such as polyethylene or polypropylene which permits the light produced by the chemiluminescent device to pass through the vessel walls.
Numerous packaging schemes for chemiluminescent devices are also well known whereby the chemical mixtures are kept separate until such time as light production is desired. U.S. Pat. No. 4,814,949 discloses a separation scheme whereby both chemical solutions are sealed in frangible vials which are housed together in a larger, flexible vessel. U.S. Pat. No. 4,379,320 discloses a co-axial vial system. U.S. Pat. No. 5,067,051 discloses a structure that maintains chemical separation by use of a disk which is situated diametrically within a plastic tube, thereby forming a barrier between the chemicals positioned on either side of the disk. When activation is desired, externally applied forces cause the disk to flip more or less 90 degrees thereby permitting mixing of the chemicals. U.S. Pat. No. 5,552,968 discloses a sphere or ball for separation of oxalate and activator component. The oxalate component in the above device may contain Dibutyl Phthalate, CPPO and CBPEA while the activator may contain the Dimethyl Phthalate, T-butyl alcohol, 90 aq. Hydrogen Peroxide, and Sodium Salicylate.
Both the oxalate and activator reagents described in the above chemiluminescent devices are prone to photo chemical degradation. That is, the chemical components undergo changes and break down upon exposure to light. While high energy, ultraviolet radiation is potentially the most damaging light to these chemical systems, even visible light causes product degradation. If these degradation processes are unchecked, the chemical solutions will eventually be degraded to such point whereby the device will fail to function. Many fluorescers such as CBPEA used in many chemiluminescent devices are severely degraded after just one day's exposure to sunlight. Additionally, hydrogen peroxide will degrade upon exposure to light. This combined degradation limits shelf life and product usefulness.
Product packaging is typically how chemiluminescent chemicals are protected from light to promote product shelf life. For example, product packaging for chemiluminescent light sticks have been produced from optically opaque, metallic foil and plastic film laminates to shield the chemiluminescent reagents from photo degradation whether from natural or artificial light. Another method to protect chemiluminescent products from photo degradation is to package the chemiluminescent devices in bulk, either in metal buckets or cardboard tubes. In either event, external product packaging, whether it be a foil wrapper or cardboard tubes, once opened or damaged may allow light to contact the chemical reagents leading to the photo degradation.
Another problem with external product packaging is the need to open the package before usage of the chemiluminescent device. In an emergency situation, should an individual's hand be wet or in a weakened condition, this extra step may render the device unusable. In emergency situations it is impractical to remove a chemiluminescent device from foil wrappers prior to activation. Also, tools may not be readily available to open the buckets or cardboard tubes of bulk packaged products. Additionally, metal films are subject to corrosion when in the prolonged presence of moisture which limits their effective application in this instance. External packaging, if improperly discarded, presents a waste product that is not readily recycled and hence is usually relegated to incineration or a landfill.
U.S. Pat. No. 4,814,949 discloses a chemiluminescent device formed from two polymeric sheets, one of which has a cavity formed into it for receipt of an absorbent article and chemiluminescent reagents. The second polymeric sheet is sealed peripherally to the first sheet to seal in the aforementioned absorbent article and receptacles. Activation may be accomplished through the application of a force on the polymeric sheet which causes the receptacles to rupture and the reagents to mix. While '949 protects chemical reagents from actinic light, the device is simply a heat sealed pouch fabricated from a polyolefin/foil laminate. Metallic foil laminates are expensive and if a pouch is used instead of vials, chemical migration through the heat seal layer is possible. Hydrogen peroxide activators exhibit a propensity for migration through polyolefins and most other polymers. Even small traces of these peroxygens are capable of rendering the oxalate reagent incapable of producing light.
Thus, what is lacking in the art is a chemiluminescent product having a light shield formed integral thereto for the protection of chemical reagents from photo degradation while maintaining a chemiluminescent device having similar properties of light production and easy instant activation when needed.